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Effect of Surface Preparation Grades of Weld Seam on the Coating Performance in Marine Structures

Effect of Surface Preparation Grades of Weld Seam on the Coating Performance in Marine Structures
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According to the international surface preparation standard for welds (ISO8501-3), the preparation grades before the application of paints are divided into 3 levels, P1, P2 and P3. These grades are described with rough qualitative representations, not description of surface treatment methods or measurable conditions. Because of the ambiguous wordings on the standard, there have been a lot of arguments for the surface preparation grades and abraded condition during the construction. 

Product Number: 51218-150-SG
Author: Sangmoon Shin
Publication Date: 2018
Industry: Coatings
$0.00
$20.00
$20.00

According to the international surface preparation standard for welds (ISO8501-3), the preparation grades before the application of paints are divided into 3 levels, P1, P2 and P3. These grades are described with rough qualitative representations, not description of surface treatment methods or measurable conditions. Because of the ambiguous wordings on the standard, there have been a lot of arguments for the surface preparation grades and abraded condition during the construction. In this study, coating thickness, the corrosion resistance and crack tendency of the coated films on the welds were evaluated for the grinding range in 5 levels from mild to severe. Each grinded specimen was blasted to Sa 2.5 and coated with 2 coats of epoxy paints. The performances of coatings on welds with the grades of grinding condition were not significantly different, satisfying the criteria of ISO 12944 (C5-M medium). After blasting, all of grinded specimens showed smooth surface which cannot make a sharp edge or excessive film thickness.

According to the international surface preparation standard for welds (ISO8501-3), the preparation grades before the application of paints are divided into 3 levels, P1, P2 and P3. These grades are described with rough qualitative representations, not description of surface treatment methods or measurable conditions. Because of the ambiguous wordings on the standard, there have been a lot of arguments for the surface preparation grades and abraded condition during the construction. In this study, coating thickness, the corrosion resistance and crack tendency of the coated films on the welds were evaluated for the grinding range in 5 levels from mild to severe. Each grinded specimen was blasted to Sa 2.5 and coated with 2 coats of epoxy paints. The performances of coatings on welds with the grades of grinding condition were not significantly different, satisfying the criteria of ISO 12944 (C5-M medium). After blasting, all of grinded specimens showed smooth surface which cannot make a sharp edge or excessive film thickness.

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